This invention relates to a machine for checking the continuity of a fibre web, more particularly a gauze in a machine preparatory to spinning, such as for example a combing machine.
Apparatus of this kind is provided in combing machines for cotton in order to cause the machine stop in the case in which the feeding gauze is lacking.
The devices of the kind referred to above which are known for stopping the machine comprise, for example, lever feelers which detect the diameter of the gauze rollers as wrapped around a paperboard hub. The lever, as the gauze has been totally paid out, is capable of acting upon a switch which opens the power circuit of the machine and stops the latter.
The conventional devices are supposed to detect the instant of time at which the thickness of the gauze wrapped around the paperboard hub is reduced to nil. Actually, however, the start of the action of the device takes place well before, inasmuch as it is difficult to provide an adjustment which is capable of having the switch entering action as the unwrapping of the gauze is over.
This fact, of course, entails the drawback that material to be processed still remains on the paperboard hub as the machine is stopped. As soon as the hub is replaced by another hub which is filled, the machine which has been left on the former hub must thus be removed, that which is a loss both of production and time.
The conventional devices, moreover, do not enter action as an accidental interruption of the web takes place.
An object of this invention is to do away with the drawbacks outlined above while providing an apparatus which enters action only as the hub is completely emptied.
Another object of the invention is to provide a machine having an extremely simple structure which can be manufactured at a low cost.